The vibrational states in a realistic model of amorphous iron

Yamamoto, Ryōichi; Haga, Kazuko; Mihara, T.; Doyama, Masao

doi:10.1088/0305-4608/10/7/008

Cited by 31 publications

(6 citation statements)

References 24 publications

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“…The dashed curve was calculated using D (x) from the specific heat data (dashed line in figure 7) according to equation ( 9). The best fit was achieved using A = 7.4 instead of A = 6.2 found for crystalline samples [39,40]. The strong increase of δ with decreasing D (x) is connected to the decrease of the number density [38].…”

Section: Vibrational Contributions To the Specific Heatmentioning

confidence: 92%

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The specific heat and upper critical field of amorphous - electronic and vibrational excitations

Sohn¹,

Baumann²

1996

J. Phys.: Condens. Matter

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The specific heat C of amorphous films was investigated between 0.3 K and 7 K in the superconducting state as well as in the normal state using a modified AC method. The analysis of the data allows one to determine the electronic density of states at the Fermi energy , the density of states of low-energy excitations and the Debye temperature . The concentration dependence of shows a pronounced minimum at x = 60 at.% in comparison to the free-electron model, in agreement with specific heat and UPS measurements and theoretical calculations published recently. The specific heat of the low-energy excitations is of the same order of magnitude as data available from the literature, and shows a linear temperature dependence. increases with copper concentration and the values agree with those published recently. In addition, the critical magnetic field of the same films was measured. The analysis of these data which should be valid for strongly disordered superconductors yields values of which are about 20% higher than those determined by specific heat measurements. Arguments are given as to why values taken from critical field measurements might be too high. Finally, the specific heat of an amorphous film was measured. was found to be 30% below the free-electron model value, in contrast to results published previously by Rieger and Baumann who found to be in accordance with the free-electron model.

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Section: Vibrational Contributions To the Specific Heatmentioning

confidence: 92%

“…Yamamoto et al derived the same dependence from a model for a-Fe [40]. The dashed curve was calculated using D (x) from the specific heat data (dashed line in figure 7) according to equation ( 9).…”

Section: Vibrational Contributions To the Specific Heatmentioning

confidence: 98%

The specific heat and upper critical field of amorphous - electronic and vibrational excitations

Sohn¹,

Baumann²

1996

J. Phys.: Condens. Matter

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“…The LDOS at the site of i-th ion in the α-th Cartesian direction is calculated using the expression: [17] …”

Section: Calculation Methodsmentioning

confidence: 99%

Interstitial-oxygen induced localized vibrational properties in alpha-quartz

Kislov

Zatsepin

2013

Journal of Non-Crystalline Solids

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Local configurations and localized vibrations of oxygen interstitials in different charged states in alpha-quartz are investigated by computer calculations. First-principle potentials of the Buckingham type have been used in numerical modeling. The study of the lattice dynamics in defective crystal is performed using the phonon local density of states. Frequencies of localized vibrations induced by oxygen interstitials are determined. It is shown that the atomic configuration, type, number and frequency of localized vibrations depend on the sign and magnitude of the interstitial atom charge.

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“…The dynamics of the Fe crystal has been determined by a lattice dynamics calculation of a crystalline slab with translation symmetry in the x and y directions and a finite number of layers along z . We have used the potential model by ref , where the interaction between the Fe atoms are given by The energy is in eV and the distance r in Å. The parameters in the potential are determined from a lattice dynamics calculation of the density of states and an experimental determination by inelastic incoherent neutron scattering .…”

Section: Application To the N2/fe(111) Systemmentioning

confidence: 99%

The Effect of the Atomic Dynamics in a Crystalline Catalyst on the Rate Constant for a Catalyzed Chemical Reaction

Hansen¹

2004

J. Phys. Chem. A

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Transition-state theory is often used to calculate the rate constant of a chemical reaction. Usually, it gives quite good results for gas-phase reactions but not for reactions in solution since the interactions of the solvent molecules with the reactants are not included in the theory. Kramers formulated an extension of the transition-state theory that included these interactions. They are represented by a friction coefficient that often is related to the viscosity of the solvent by Stoke's law. For reactions on the surface of a crystalline catalyst, there will also be an effect on the rate constant from the interaction between the reactants and the oscillating substrate atoms. In contrast to reactions in solution, where the friction coefficient is related to the viscosity of the solvent, there exists no simple property of the solid that may be directly related to a friction coefficient for the motion of the adsorbed molecule on the surface. In this paper, we propose a method that may be used to calculate a friction coefficient that may be used in Kramers theory to calculate the rate constant for a chemical reaction on the surface of a crystalline solid.

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The vibrational states in a realistic model of amorphous iron

Cited by 31 publications

References 24 publications

The specific heat and upper critical field of amorphous - electronic and vibrational excitations

The specific heat and upper critical field of amorphous - electronic and vibrational excitations

Interstitial-oxygen induced localized vibrational properties in alpha-quartz

The Effect of the Atomic Dynamics in a Crystalline Catalyst on the Rate Constant for a Catalyzed Chemical Reaction

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